I have a problem with the brakes locking up immediately

2000 GMC SIERRA
210,000 MILES • V8 • 4WD • AUTOMATIC
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MNMOUDRY
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I have a classic 2500HD Sierra. When the brakes receive any type of excessive moisture(heavy rain or snow, boat landings) I have a problem with the brakes locking up immediately with the slightest bit of brake pressure. Once they dry off on the road they are fine. My mechanic can find nothing wrong(said it was brake dust) and it never does it when I bring it in. The brake dust has been cleaned out but it still continues to be a problem! Is this an ABS issue?
Thank you-
Mar 30, 2010 at 12:08 PM
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2CARPRO JACK
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2000 was a transition year......... does it have disc or drum rear brakes? If drum, it sounds like either the drum diameter is too large(machined to outer spec) or relined shoes were used and they are making too much contact with the drum surface.If they are discs, you may want to try another brand of pads.The ABS system wont lock up the brakes, it is designed to release brake pressure to keep that from happening
May 8, 2021 at 12:56 PM
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MNMOUDRY
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They are drum brakes. I haven't had to replace the shoes yet. They don't seem to be wearing down much. I believe everything in the back is still factory. How would moisture affect the problems you suggested?
Thank you-
May 8, 2021 at 12:56 PM
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2CARPRO JACK
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The moisture keeps the brake material from becoming dust, which can cause an extra grip type of situation, as well as surface rust, which can build up in a matter of minutes on braking surfaces.
May 8, 2021 at 12:56 PM